Abstract: Industrial wastewater frequently contains priority pollutants like chromium, which tend to form complexes with organic molecules. These complexes are challenging to remove, often leading to substantial environmental discharge. In this study, Selenastrum capricornutum served as the model organism to investigate the biological impact of various multiligand chromium complexes on algal cells. Results showed that the multiligand chromium complexes significantly elevated the level of reactive oxygen species (ROS) in the algal cells (increases of 44% to 55%), which induced oxidative stress and consequently inhibited algal growth to different extents (inhibition rates ranged from 16% to 67%). Extended exposure further hindered the synthesis of soluble proteins and carbohydrates in Selenastrum capricornutum. Notably, gelatin-gallic acid-chromium complexes were identified as the most biotoxic of the multiligand chromium complexes studied. Furthermore, Selenastrum capricornutum exhibited some degree of biodegradation of these complexes after long-term co-cultivation. These findings suggest that multiligand chromium complexes could pose considerable risks to aquatic ecosystems.